The prior art includes various types of cleaning devices and other machines which have various types of liquid heating assemblies for heating a cleaning fluid and which is subsequently sprayed onto an object to be cleaned and then suctioned back into a recovery tank. An example of such a prior art device is found in U.S. Pat. No. 4,803,466, the teachings of which are incorporated by reference herein. The device exemplified by the aforementioned patent utilizes an electrical heater which has a corresponding heat exchanger. This assembly heats the fluid to be applied to a given temperature before it is applied to the surface which is to be cleaned.
While devices as exemplified in U.S. Pat. No. 4,803,466 have operated with a great deal of success, there are various shortcomings attendant with these prior art assemblies which have detracted from their usefulness. More specifically, such devices as exemplified by this, and other U.S. patents, as a general matter, require a large amount of electrical power in order to sufficiently heat the fluids which are to be applied. Because electrical outlets capable of delivering more than 1800 watts are relatively uncommon in residential and commercial buildings in North America, compromises in temperature rise and/or fluid flow rate must necessarily be made. Consequently, such devices cannot clean carpets as quickly as could devices that had greater power. Furthermore, dependence upon electrical cords for power requires an operator of such prior art devices to start and stop these prior art machines several times when the operator is cleaning a given area, such as a floor, in order to move his power cable to the power outlet most near the area where the cleaning machine is operating. This activity, of course, further slows the progress of cleaning, and also presents inconveniences inasmuch as power cables of the type described often present safety concerns in the form of a tripping hazard for people traveling in the near vicinity of these cleaning machines as they are operating.
In addition to the foregoing, and in some environments, the power cables of such machines may not have a length which will permit such cleaning devices to reach some remote areas. This is often the case in large department stores, and the like, where fixtures such as shelves, displays and counters would inhibit the direct routing of the power cable servicing the cleaning machine which is operating in the area which is being cleaned.
To address this perceived shortcoming, various cleaning devices and machines have been introduced and which include self contained power supplies. These devices typically consist of multiple lead-acid batteries which are utilized to supply power to the cleaning device so it may operate remotely relative to an AC power source.
While cleaning devices having self contained power sources have operated with some degree of success, the useful operational time of such devices is quite limited. Consequently, an operator must periodically stop these prior art machines either to recharge the batteries utilized with same; or in the alternative, remove the discharged batteries, and replace them with a fully charged set of batteries, so that the machine can continue in operation. This activity of either on the one hand, recharging the batteries, or replacing the discharged batteries with charged batteries further increases the cost and amount of time necessary to clean a given article or area. Those skilled in the art will readily recognize that the continuous and repeated deep discharging of rechargeable batteries will typically shorten the life expectancy of such batteries such that they may need to be replaced on a fairly regular timetable. Still further, machines of this type which have rechargeable batteries which power same are also relatively speaking, large, quite heavy, and difficult to maneuver in small spaces. Still further, the devices are often difficult to maintain.
Therefore, a cleaning machine which overcomes many of the perceived shortcomings of the prior art devices and practices is the subject matter of the present application.